Abstract
This paper presents a re-evaluation of the taxonomic identity of Gastrodia foetida based on molecular and morphological data. The taxon was described from Iriomote Island, Ryukyu Islands, Japan, and has often been treated as a synonym of G. nipponica from Wakayama Prefecture, Honshu, Japan. In contrast, we showed that the genetic divergence between G. foetida and G. nipponica is much more significant than that between G. foetida and G. takeshimensis. Additionally, G. foetida can be distinguished from G. nipponica by a few morphological traits, particularly a more dilated column toward a little below the middle. Therefore, we propose that G. foetida is recognized as a distinct species based primarily on molecular phylogenetic evidence followed by morphological evidence. Our investigation strongly suggested that these species exhibit distinct geographic separation: G. nipponica is restricted in mainland Japan (north of the Ryukyu Islands), whereas G. foetida is mainly distributed on the more southern areas (the Ryukyu Islands and possibly Taiwan).
References
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<p>Hsu, T.C., Chung, S.W. & Kuo, C.M. (2012) Supplements to the orchid flora of Taiwan (vi). <em>Taiwania</em> 57: 271–277.</p>
<p>Hsu, T.-C., Fanerii, M., Yang, T.-Y.A., Pitisopa, F. & Li, C.-W. (2016) <em>Gastrodia isabelensis</em> and <em>G. solomonensis</em> (Gastrodieae, Epidendroideae, Orchidaceae): two new species representing a new generic record in the Solomon Islands. <em>Phytotaxa</em> 270 (2): 137–145. https://doi.org/10.11646/phytotaxa.270.2.6</p>
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<p>Koidzumi, G. (1940) Contributiones ad cognitionem florae Asiae Orientalis. <em>Acta Phytotaxonomica et Geobotanica</em> 9: 71. https://doi.org/10.18942/bunruichiri.KJ00002594589</p>
<p>Langella, O. (2007) Populations ver. 1.2. 30: population genetic software (individuals or populations distances, phylogenetic trees). [http://bioinformatics.org/∼tryphon/populations/]</p>
<p>Lin, T.-P. (2019) <em>The orchid flora of Taiwan: A collection of line drawings</em>. National Taiwan University Press, Taipei, 1012 pp.</p>
<p>Ma, L., Chen, X., Liu, J. & Chen, S. (2019) <em>Gastrodia fujianensis</em> (Orchidaceae, Epidendroideae, Gastrodieae), a new species from China. <em>Phytotaxa</em> 391 (4): 269–272. https://doi.org/10.11646/phytotaxa.391.4.5</p>
<p>Metusala, D. & Supriatna, J. (2017) <em>Gastrodia bambu</em> (Orchidaceae: Epidendroideae), a new species from Java, Indonesia. <em>Phytotaxa</em> 317 (3): 211–218. https://doi.org/10.11646/phytotaxa.317.3.5</p>
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<p>Ogaki, K., Suetsugu, K., Kishikawa, K., Kyogoku, D., Shutoh, K., Isagi, Y. & Kaneko, S. (2019) New microsatellite markers recognize differences in tandem repeats among four related <em>Gastrodia</em> species (Orchidaceae). <em>Genes & Genetic Systems</em> 94: 225–229. https://doi.org/10.1266/ggs.19-00025</p>
<p>Ong, P. & O’Byrne, P. (2012) Two new species of <em>Gastrodia</em> from Terengganu, Peninsular Malaysia. <em>Malesian Orchid Journal</em> 10: 7–16.</p>
<p>Pelser, P.B., Doble, K.J.S., O’BYRNE, P., Ormerod, P. & Barcelona, J.F. (2016) <em>Gastrodia cajanoae</em> (Orchidaceae: Epidendroideae: Gastrodieae), a new species from the Philippines. <em>Phytotaxa</em> 266 (1): 53–56. https://doi.org/10.11646/phytotaxa.266.1.9</p>
<p>Suetsugu, K. (2013) <em>Gastrodia takeshimensis</em> (Orchidaceae), a new mycoheterotrophic species from Japan. <em>Annales Botanici Fennici</em> 50: 375–378. https://doi.org/10.5735/085.050.0613</p>
<p>Suetsugu, K. (2014) <em>Gastrodia flexistyloides</em> (Orchidaceae), a new mycoheterotrophic plant with complete cleistogamy from Japan. <em>Phytotaxa</em> 175 (5): 270–274. https://doi.org/10.11646/phytotaxa.175.5.5</p>
<p>Suetsugu, K. (2016) <em>Gastrodia kuroshimensis</em> (Orchidaceae), a new mycoheterotrophic and complete cleistogamous plant from Japan. <em>Phytotaxa</em> 278 (3): 265–272. https://doi.org/10.11646/phytotaxa.278.3.6</p>
<p>Suetsugu, K. (2017) Two new species of <em>Gastrodia</em> (Gastrodieae, Epidendroideae, Orchidaceae) from Okinawa Island, Ryukyu Islands, Japan. <em>Phytotaxa</em> 302 (3): 251–258. https://doi.org/10.11646/phytotaxa.302.3.4</p>
<p>Suetsugu, K. (2018) The northernmost locality of the mycoheterotrophic orchid <em>Gastrodia flexistyloides</em> from Fukuejima island, Nagasaki Prefecture, Japan. <em>Japan. Journal of Japanese Botany</em> 93: 61–64.</p>
<p>Suetsugu, K. (2019) <em>Gastrodia amamiana</em> (Orchidaceae; Epidendroideae; Gastrodieae), a new completely cleistogamous species from Japan. <em>Phytotaxa</em> 413 (3): 225–230. https://doi.org/10.11646/phytotaxa.413.3.3</p>
<p>Suetsugu, K. (2021) <em>Gastrodia longiflora</em> (Orchidaceae: Epidendroideae: Gastrodieae), a new mycoheterotrophic species from Ishigaki Island, Ryukyu Islands, Japan. <em>Phytotaxa</em> 502 (1): 107–110. https://doi.org/10.11646/phytotaxa.502.1.9</p>
<p>Suetsugu, K. (2022) Living in the shadows: <em>Gastrodia</em> orchids lack functional leaves and open flowers. <em>Plants, People, Planet</em> 4: 418–422. https://doi.org/10.1002/ppp3.10281</p>
<p>Suetsugu K. & Fukunaga, H. (2017) A new locality of <em>Lecanorchis tabugawaensis</em> (Orchidaceae) from Fukuejima Island, Nagasaki Prefecture, Japan. <em>Bunrui</em> 17: 71–73. https://doi.org/10.18942/bunrui.01701-11</p>
<p>Suetsugu, K., Fukushima, K., Makino, T., Ikematsu, S., Sakamoto, T. & Kimura, S. (2023) Transcriptomic heterochrony and completely cleistogamous flower development in the mycoheterotrophic orchid <em>Gastrodia</em>. <em>New Phytologist </em>237: 323–338. https://doi.org/10.1111/nph.18495</p>
<p>Suetsugu, K., Suleiman, M. & Tsukaya, H. (2018) A new species of <em>Gastrodia</em> (Gastrodieae, Epidendroideae, Orchidaceae) from the Maliau Basin Conservation Area, Sabah, Borneo. <em>Phytotaxa</em> 367 (1): 78–84. https://doi.org/10.11646/phytotaxa.367.1.9</p>
<p>Tan, Y.H., Hsu, T.C., Pan, B., Li, J.W. & Liu, Q. (2012) <em>Gastrodia albidoides</em> (orchidaceae: Epidendroideae), a new species from Yunnan, China. <em>Phytotaxa</em> 66 (1): 38–42. https://doi.org/10.11646/phytotaxa.66.1.6</p>
<p>Thiers, B. (2022) Index Herbariorum, New York Botanical Garden. Available from: http://sweetgum.nybg.org/science/ih/ (6 October, 2022)</p>
<p>Tsukaya, H. & Hidayat, A. (2016) A new species of <em>Gastrodia</em> (Orchidaceae: Gastrodieae, Epidendroideae) from Java. <em>Phytotaxa</em> 273 (1): 77–80. https://doi.org/10.11646/phytotaxa.273.1.9</p>
<p>Tuyama, T. (1939) Plantæ Boninenses Novæ vel Criticæ. XII. <em>The Botanical Magazine (Tokyo)</em> 53: 1–7. https://doi.org/10.15281/jplantres1887.53.1</p>
<p>Bandara, C., Priyankara, T., Atthanagoda, A.G., Lakkana, T., Ediriweera, S. & Kumar, P. (2020) <em>Gastrodia gunatillekeorum</em> (Gastrodieae, Epidendroideae, Orchidaceae), a new species from a lowland rainforest of Sri Lanka. <em>Phytotaxa</em> 436 (1): 55–62. https://doi.org/10.11646/phytotaxa.436.1.5</p>
<p>Brown, R. (1810) <em>Prodromus florae novae Hollandae et insulae Van-Diemen</em>. 1st ed. Taylor, London, 592 pp.</p>
<p>Cribb, P., Fischer, E. & Killmann, D. (2010) A revision of <em>Gastrodia</em> (Orchidaceae: Epidendroideae, Gastrodieae) in tropical Africa. <em>Kew Bulletin</em> 65: 315–321. https://doi.org/10.1007/s12225-010-9193-4</p>
<p>Honda, M. (1932) On a new species of <em>Didymoplexis</em>. <em>The Botanical Magazine (Tokyo)</em> 46: 168. https://doi.org/10.15281/jplantres1887.46.168</p>
<p>Hsu, T.C., Chung, S.W. & Kuo, C.M. (2012) Supplements to the orchid flora of Taiwan (vi). <em>Taiwania</em> 57: 271–277.</p>
<p>Hsu, T.-C., Fanerii, M., Yang, T.-Y.A., Pitisopa, F. & Li, C.-W. (2016) <em>Gastrodia isabelensis</em> and <em>G. solomonensis</em> (Gastrodieae, Epidendroideae, Orchidaceae): two new species representing a new generic record in the Solomon Islands. <em>Phytotaxa</em> 270 (2): 137–145. https://doi.org/10.11646/phytotaxa.270.2.6</p>
<p>Hsu, T.C. & Kuo, C.M. (2010) Supplements to the orchid flora of Taiwan (IV): Four additions to the genus <em>Gastrodia</em>. <em>Taiwania</em> 55: 243–248.</p>
<p>Kishikawa, K., Suetsugu, K., Kyogoku, D., Ogaki, K., Iga, D., Shutoh, K., Isagi, Y. & Kaneko, S. (2019) Development of microsatellite markers for the completely cleistogamous species <em>Gastrodia takeshimensis</em> (Orchidaceae) that are transferable to its chasmogamous sister <em>G. nipponica</em>. <em>Genes & Genetic Systems</em> 94: 95–98. https://doi.org/10.1266/ggs.18-00057</p>
<p>Koidzumi, G. (1940) Contributiones ad cognitionem florae Asiae Orientalis. <em>Acta Phytotaxonomica et Geobotanica</em> 9: 71. https://doi.org/10.18942/bunruichiri.KJ00002594589</p>
<p>Langella, O. (2007) Populations ver. 1.2. 30: population genetic software (individuals or populations distances, phylogenetic trees). [http://bioinformatics.org/∼tryphon/populations/]</p>
<p>Lin, T.-P. (2019) <em>The orchid flora of Taiwan: A collection of line drawings</em>. National Taiwan University Press, Taipei, 1012 pp.</p>
<p>Ma, L., Chen, X., Liu, J. & Chen, S. (2019) <em>Gastrodia fujianensis</em> (Orchidaceae, Epidendroideae, Gastrodieae), a new species from China. <em>Phytotaxa</em> 391 (4): 269–272. https://doi.org/10.11646/phytotaxa.391.4.5</p>
<p>Metusala, D. & Supriatna, J. (2017) <em>Gastrodia bambu</em> (Orchidaceae: Epidendroideae), a new species from Java, Indonesia. <em>Phytotaxa</em> 317 (3): 211–218. https://doi.org/10.11646/phytotaxa.317.3.5</p>
<p>Nei, M., Tajima, F. & Tateno, Y. (1983) Accuracy of estimated phylogenetic trees from molecular data - II. Gene frequency data. <em>Journal of Molecular Evolution</em> 19: 153–170. https://doi.org/10.1007/BF02300753</p>
<p>Ogaki, K., Suetsugu, K., Kishikawa, K., Kyogoku, D., Shutoh, K., Isagi, Y. & Kaneko, S. (2019) New microsatellite markers recognize differences in tandem repeats among four related <em>Gastrodia</em> species (Orchidaceae). <em>Genes & Genetic Systems</em> 94: 225–229. https://doi.org/10.1266/ggs.19-00025</p>
<p>Ong, P. & O’Byrne, P. (2012) Two new species of <em>Gastrodia</em> from Terengganu, Peninsular Malaysia. <em>Malesian Orchid Journal</em> 10: 7–16.</p>
<p>Pelser, P.B., Doble, K.J.S., O’BYRNE, P., Ormerod, P. & Barcelona, J.F. (2016) <em>Gastrodia cajanoae</em> (Orchidaceae: Epidendroideae: Gastrodieae), a new species from the Philippines. <em>Phytotaxa</em> 266 (1): 53–56. https://doi.org/10.11646/phytotaxa.266.1.9</p>
<p>Suetsugu, K. (2013) <em>Gastrodia takeshimensis</em> (Orchidaceae), a new mycoheterotrophic species from Japan. <em>Annales Botanici Fennici</em> 50: 375–378. https://doi.org/10.5735/085.050.0613</p>
<p>Suetsugu, K. (2014) <em>Gastrodia flexistyloides</em> (Orchidaceae), a new mycoheterotrophic plant with complete cleistogamy from Japan. <em>Phytotaxa</em> 175 (5): 270–274. https://doi.org/10.11646/phytotaxa.175.5.5</p>
<p>Suetsugu, K. (2016) <em>Gastrodia kuroshimensis</em> (Orchidaceae), a new mycoheterotrophic and complete cleistogamous plant from Japan. <em>Phytotaxa</em> 278 (3): 265–272. https://doi.org/10.11646/phytotaxa.278.3.6</p>
<p>Suetsugu, K. (2017) Two new species of <em>Gastrodia</em> (Gastrodieae, Epidendroideae, Orchidaceae) from Okinawa Island, Ryukyu Islands, Japan. <em>Phytotaxa</em> 302 (3): 251–258. https://doi.org/10.11646/phytotaxa.302.3.4</p>
<p>Suetsugu, K. (2018) The northernmost locality of the mycoheterotrophic orchid <em>Gastrodia flexistyloides</em> from Fukuejima island, Nagasaki Prefecture, Japan. <em>Japan. Journal of Japanese Botany</em> 93: 61–64.</p>
<p>Suetsugu, K. (2019) <em>Gastrodia amamiana</em> (Orchidaceae; Epidendroideae; Gastrodieae), a new completely cleistogamous species from Japan. <em>Phytotaxa</em> 413 (3): 225–230. https://doi.org/10.11646/phytotaxa.413.3.3</p>
<p>Suetsugu, K. (2021) <em>Gastrodia longiflora</em> (Orchidaceae: Epidendroideae: Gastrodieae), a new mycoheterotrophic species from Ishigaki Island, Ryukyu Islands, Japan. <em>Phytotaxa</em> 502 (1): 107–110. https://doi.org/10.11646/phytotaxa.502.1.9</p>
<p>Suetsugu, K. (2022) Living in the shadows: <em>Gastrodia</em> orchids lack functional leaves and open flowers. <em>Plants, People, Planet</em> 4: 418–422. https://doi.org/10.1002/ppp3.10281</p>
<p>Suetsugu K. & Fukunaga, H. (2017) A new locality of <em>Lecanorchis tabugawaensis</em> (Orchidaceae) from Fukuejima Island, Nagasaki Prefecture, Japan. <em>Bunrui</em> 17: 71–73. https://doi.org/10.18942/bunrui.01701-11</p>
<p>Suetsugu, K., Fukushima, K., Makino, T., Ikematsu, S., Sakamoto, T. & Kimura, S. (2023) Transcriptomic heterochrony and completely cleistogamous flower development in the mycoheterotrophic orchid <em>Gastrodia</em>. <em>New Phytologist </em>237: 323–338. https://doi.org/10.1111/nph.18495</p>
<p>Suetsugu, K., Suleiman, M. & Tsukaya, H. (2018) A new species of <em>Gastrodia</em> (Gastrodieae, Epidendroideae, Orchidaceae) from the Maliau Basin Conservation Area, Sabah, Borneo. <em>Phytotaxa</em> 367 (1): 78–84. https://doi.org/10.11646/phytotaxa.367.1.9</p>
<p>Tan, Y.H., Hsu, T.C., Pan, B., Li, J.W. & Liu, Q. (2012) <em>Gastrodia albidoides</em> (orchidaceae: Epidendroideae), a new species from Yunnan, China. <em>Phytotaxa</em> 66 (1): 38–42. https://doi.org/10.11646/phytotaxa.66.1.6</p>
<p>Thiers, B. (2022) Index Herbariorum, New York Botanical Garden. Available from: http://sweetgum.nybg.org/science/ih/ (6 October, 2022)</p>
<p>Tsukaya, H. & Hidayat, A. (2016) A new species of <em>Gastrodia</em> (Orchidaceae: Gastrodieae, Epidendroideae) from Java. <em>Phytotaxa</em> 273 (1): 77–80. https://doi.org/10.11646/phytotaxa.273.1.9</p>
<p>Tuyama, T. (1939) Plantæ Boninenses Novæ vel Criticæ. XII. <em>The Botanical Magazine (Tokyo)</em> 53: 1–7. https://doi.org/10.15281/jplantres1887.53.1</p>